Title

A Multicenter Phase 3, Open-Label Study of Bosutinib Versus Imatinib in Adult Patients With Newly Diagnosed Chronic Phase Chronic Myelogenous Leukemia
A MULTICENTER PHASE 3 RANDOMIZED, OPEN-LABEL STUDY OF BOSUTINIB VERSUS IMATINIB IN ADULT PATIENTS WITH NEWLY DIAGNOSED CHRONIC PHASE CHRONIC MYELOGENOUS LEUKEMIA
  • Phase

    Phase 3
  • Study Type

    Interventional
  • Study Participants

    536
Phase 3, 2-arm, randomized, open label trial. Patients will be randomized to receive bosutinib or imatinib for the duration of the study.
The study will be open for enrollment until the planned number of approximately 500 Philadelphia Chromosome Positive (Ph+) patients have been randomized (approximately 250 Ph+ patients in each treatment arm; a total of approximately 530 Ph+ and Ph- patients). All patients will be treated and/or followed for approximately 5 years (240 weeks) after randomization until the study has closed. Patients who discontinue study therapy early due to disease progression or intolerance to study medication will continue to be followed yearly for survival for up to approximately 5 years (240 weeks) after randomization.
Study Started
Jul 15
2014
Primary Completion
Aug 11
2016
Study Completion
Apr 17
2020
Results Posted
Nov 14
2018
Last Update
May 18
2021

Drug Bosutinib

Bosutinib (Bosulif®) is an orally bioavailable, potent, multi-targeted, dual Src-Abl tyrosine kinase inhibitor (TKI) that has been approved for the treatment of adult patients with Philadelphia positive (Ph+) chronic phase (CP), accelerated phase (AP) and blast phase (BP) chronic myelogenous leukemia (CML) previously treated with other TKI inhibitor therapy.[1] This study will investigate the use of bosutinib as first-line treatment for patients with Ph+ CP CML.

Drug Imatinib

Imatinib mesylate (referred to in this protocol as imatinib) is an inhibitor of the BCR-ABL kinase and been the standard first-line therapy for patients with chronic-phase CML. Imatinib was granted approval by the European Commission in November 2001 and by the FDA in December 2002 for the treatment of newly diagnosed patients with CP Ph+ CML based on results from the IRIS trial. Imatinib is considered the standard of care for both first-line and later line settings, and consequently is an appropriate active comparator.

Bosutinib Experimental

Bosutinib, 400 mg, oral administration once a day

Imatinib Active Comparator

Imatinib, 400 mg, oral administration once a day

Criteria

Inclusion Criteria:

Molecular diagnosis of CP CML of ≤ 6 months (from initial diagnosis).
Adequate hepatic, renal and pancreatic function.
Age ≥ 18 years.

Exclusion Criteria:

Any prior medical treatment for CML, including tyrosine kinase inhibitors (TKIs), with the exception of hydroxyurea and/or anagrelide treatment, which are permitted for up to 6 months prior to study entry (signature of ICF) if suitably approved for use in the subject's region.
Any past or current Central Nervous System (CNS) involvement, including leptomeningeal leukemia.
Extramedullary disease only.
Major surgery or radiotherapy within 14 days of randomization.
History of clinically significant or uncontrolled cardiac disease.
Known seropositivity to human immunodeficiency virus (HIV), current acute or chronic hepatitis B (hepatitis B surface-antigen positive), hepatitis C, cirrhosis or evidence of decompensated liver disease. Patients with resolved Hepatitis B can be included.
Recent or ongoing clinically significant GI disorder, e.g. Crohn's Disease, Ulcerative Colitis, or prior total or partial gastrectomy.
History of another malignancy within 5 years with the exception of basal cell carcinoma or cervical carcinoma in situ or stage 1 or 2 cancer that is considered adequately treated and currently in complete remission for at least l2 months.
Current, or recent (within 30 days, or 5 half-lives of investigational product) participation in other clinical trials of investigational agents and/or containing interventional procedures deemed contrary to the objectives and conduct of this trial.

Summary

Bosutinib

Imatinib

All Events

Event Type Organ System Event Term Bosutinib Imatinib

Percentage of Participants With Major Molecular Response (MMR) at Month 12

MMR was defined as a ratio of breakpoint cluster region to abelson (BCR-ABL/ABL) less than or equal to (<=) 0.1 percent (%) on the international scale (IS) (greater than or equal to [>=] 3 log reduction from standardized baseline in ratio of BCR-ABL to ABL transcripts [>=3000 ABL required]) by quantitative reverse transcriptase polymerase chain reaction (RT-qPCR). The percentage of participants with MMR at Month 12 are reported.

Bosutinib

47.2
percentage of participants
95% Confidence Interval: 40.9 to 53.4

Imatinib

36.9
percentage of participants
95% Confidence Interval: 30.8 to 43.0

Percentage of Participants With Major Molecular Response (MMR) Up to Month 18

MMR was defined as a ratio of BCR-ABL/ABL <=0.1% on the international scale (>=3 log reduction from standardized baseline in ratio of BCR-ABL to ABL transcripts [>=3000 ABL required]) by quantitative RT-qPCR. The percentage of participants with MMR for up to Month 18 are reported.

Bosutinib

61.0
percentage of participants
95% Confidence Interval: 54.9 to 67.1

Imatinib

52.7
percentage of participants
95% Confidence Interval: 46.4 to 59.0

Kaplan-Meier Estimate of Probability of Retaining Major Molecular Response (MMR) at Month 48

The Kaplan-Meier curve was generated based on the first date of MMR until the date of the confirmed loss of MMR or censoring, objectively documented, for responders only. Confirmed loss of MMR was BCR-ABL/ABL IS ratio >0.1% in association with a >=5-fold increase in BCR-ABL/ABL IS ratio from the lowest value achieved up to that time-point confirmed by a second assessment at least 28 days later. Treatment discontinuation due to suboptimal response/treatment failure, progressive disease (PD) or death due to PD within 28 days of last dose were considered confirmed loss of MMR. PD was defined as disease progression to accelerated phase (AP) or blast phase (BP) CML.

Bosutinib

92.2
percentage of participants
95% Confidence Interval: 86.8 to 95.4

Imatinib

92.0
percentage of participants
95% Confidence Interval: 85.9 to 95.5

Percentage of Participants With Complete Cytogenetic Response (CCyR) Up to Month 12

Complete Cytogenetic Response (CCyR) was based on the prevalence of Ph+ metaphases among cells in metaphase on a bone marrow (BM) aspirate. CCyR was achieved when there was 0% Ph+ metaphases among cells in a BM sample when at least 20 metaphases from a BM sample were analyzed, or MMR if no BM was available. The percentage of participants with CCyR for up to Month 12 are reported.

Bosutinib

77.2
percentage of participants
95% Confidence Interval: 72.0 to 82.5

Imatinib

66.4
percentage of participants
95% Confidence Interval: 60.4 to 72.4

Kaplan-Meier Estimate of Probability of Retaining Complete Cytogenetic Response (CCyR) at Month 48

The Kaplan-Meier curve was generated based on the first date of CCyR until the date of the confirmed loss of CCyR or censoring, objectively documented, for responders only. Confirmed loss of CCyR was the presence of at least one Ph+ metaphase confirmed by a second assessment at least 28 days later. Treatment discontinuation due to suboptimal response/treatment failure, PD or death due to PD within 28 days of last dose were considered confirmed loss of CCyR. PD was defined as disease progression to AP or BP CML.

Bosutinib

97.4
percentage of participants
95% Confidence Interval: 93.9 to 98.9

Imatinib

93.7
percentage of participants
95% Confidence Interval: 88.9 to 96.5

Cumulative Incidence of Event Free Survival (EFS) Events

EFS was defined as time from randomization to death due to any cause, transformation to AP or BP at any time, confirmed loss of complete hematologic response (CHR), confirmed loss of CCyR or censoring. Loss of CHR was defined as a hematologic assessment of non-CHR (chronic phase, AP, or BP) confirmed by 2 assessments at least 4 weeks apart. Loss of CHR was defined as appearance of any of the following: WBC count that rises to >20.0*10^9/L, platelet count rises to >=600*10^9/L, appearance of palpable spleen or other extramedullary involvement proven by biopsy, appearance of 5% myelocytes in peripheral blood, appearance of blasts or promyelocytes in peripheral blood. Loss of CCyR was defined as at least 1 Ph+ metaphase from analysis of <100 metaphases confirmed by follow up cytogenetic analysis after 1 month. Cumulative incidence of EFS was defined as percentage of participants with EFS event at Month 60 and was adjusted for competing risk of treatment discontinuation without event.

Bosutinib

6.9
percentage of participants
95% Confidence Interval: 4.2 to 10.5

Imatinib

10.4
percentage of participants
95% Confidence Interval: 6.9 to 14.6

Overall Survival (OS) Rate

OS was defined as the time (in months) from randomization to the occurrence of death due to any cause or censoring. Kaplan-meier analysis was used for determination of OS. Percentage of participants who were alive were estimated in this outcome measure.

Bosutinib

94.9
percentage of participants
95% Confidence Interval: 91.1 to 97.0

Imatinib

94.0
percentage of participants
95% Confidence Interval: 90.1 to 96.4

Summary of Trough Plasma Concentration by Complete Cytogenetic Response (CCyR) of Bosutinib

CCyR was based on the prevalence of Ph+ metaphases among cells in metaphase on a BM aspirate. CCyR was achieved when there was 0% Ph+ metaphases among cells in a BM sample when at least 20 metaphases from a BM sample were analyzed, or MMR if no BM was available. Trough plasma concentration of participants who had CCyR are presented in this outcome measure.

Bosutinib

Day 28

71.282
nanogram per milliliter (ng/mL) (Mean)
Standard Deviation: 46.0545

Day 56

73.069
nanogram per milliliter (ng/mL) (Mean)
Standard Deviation: 45.1349

Day 84

83.973
nanogram per milliliter (ng/mL) (Mean)
Standard Deviation: 64.3206

Summary of Trough Plasma Concentration by Major Molecular Response (MMR) of Bosutinib

MMR was defined as a ratio of BCR-ABL/ABL <=0.1% on the international scale (>=3 log reduction from standardized baseline in ratio of BCR-ABL to ABL transcripts) by quantitative RT-qPCR. Trough plasma concentration of participants who had MMR are presented in this outcome measure.

Bosutinib

Day 28

75.05
ng/mL (Mean)
Standard Deviation: 51.9551

Day 56

78.437
ng/mL (Mean)
Standard Deviation: 43.6019

Day 84

91.081
ng/mL (Mean)
Standard Deviation: 72.1500

Summary of Trough Plasma Concentration by Presence of Grade 1 or Higher Adverse Events (AEs) of Bosutinib

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. AE was assessed according to maximum severity grading based on National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Grade 1= mild; Grade 2= moderate; within normal limits, Grade 3= severe or medically significant but not immediately life-threatening; Grade 4= life-threatening or disabling; urgent intervention indicated; Grade 5= death. Trough plasma concentration of participants who had grade 1 or higher AE are presented in this outcome measure. Data of plasma concentration is reported separately for each preferred term of AE.

Bosutinib

Day 28: Diarrhea

69.402
ng/mL (Mean)
Standard Deviation: 55.5005

Day 28: Nausea

66.011
ng/mL (Mean)
Standard Deviation: 42.6437

Day 28: Rash

74.779
ng/mL (Mean)
Standard Deviation: 60.6257

Day 28: Thrombocytopenia

63.529
ng/mL (Mean)
Standard Deviation: 40.9949

Day 28: Vomiting

71.684
ng/mL (Mean)
Standard Deviation: 60.7208

Day 56: Diarrhea

68.834
ng/mL (Mean)
Standard Deviation: 42.6621

Day 56: Nausea

61.626
ng/mL (Mean)
Standard Deviation: 44.4007

Day 56: Rash

70.016
ng/mL (Mean)
Standard Deviation: 38.7506

Day 56: Thrombocytopenia

65.327
ng/mL (Mean)
Standard Deviation: 43.2859

Day 56: Vomiting

65.98
ng/mL (Mean)
Standard Deviation: 45.9064

Day 84: Diarrhea

81.269
ng/mL (Mean)
Standard Deviation: 64.6462

Day 84: Nausea

77.702
ng/mL (Mean)
Standard Deviation: 61.6179

Day 84: Rash

89.08
ng/mL (Mean)
Standard Deviation: 69.5237

Day 84: Thrombocytopenia

71.585
ng/mL (Mean)
Standard Deviation: 33.6674

Day 84: Vomiting

86.949
ng/mL (Mean)
Standard Deviation: 55.3041

Summary of Trough Plasma Concentration by Presence of Grade 3 or Higher Adverse Events (AEs) of Bosutinib

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. AE was assessed according to maximum severity grading based on NCI CTCAE version 4.0. Grade 1= mild; Grade 2= moderate; within normal limits, Grade 3= severe or medically significant but not immediately life-threatening; Grade 4= life-threatening or disabling; urgent intervention indicated; Grade 5= death. Trough plasma concentration of participants who had grade 3 or higher AE are presented in this outcome measure. Data of plasma concentration is reported separately for each preferred term of AE.

Bosutinib

Day 28: Diarrhea

87.769
ng/mL (Mean)
Standard Deviation: 102.6181

Day 28: Rash

71.15
ng/mL (Mean)
Standard Deviation: 43.3246

Day 28: Thrombocytopenia

49.22
ng/mL (Mean)
Standard Deviation: 36.3461

Day 28: Vomiting

14.663
ng/mL (Mean)
Standard Deviation: 21.5799

Day 56: Diarrhea

68.513
ng/mL (Mean)
Standard Deviation: 45.2672

Day 56: Rash

58.925
ng/mL (Mean)
Standard Deviation: 18.8656

Day 56: Thrombocytopenia

56.853
ng/mL (Mean)
Standard Deviation: 34.3892

Day 56: Vomiting

38.2
ng/mL (Mean)
Standard Deviation: NA

Day 84: Diarrhea

76.782
ng/mL (Mean)
Standard Deviation: 46.3006

Day 84: Rash

83.967
ng/mL (Mean)
Standard Deviation: 19.2542

Day 84: Thrombocytopenia

67.623
ng/mL (Mean)
Standard Deviation: 35.3084

Day 84: Vomiting

12.4
ng/mL (Mean)
Standard Deviation: NA

Number of Participants With Vital Signs Abnormalities

Criteria for vital signs abnormalities: systolic blood pressure <80 millimeter of mercury (mmHg), >210 mmHg; diastolic blood pressure <40 mmHg, >130 mmHg; heart rate <40 beats per minute (bpm), >150 bpm; temperature <32 degree celsius, >40 degree celsius; weight >=10% increase from baseline, >=10% decrease from baseline. The number of participants with any vital sign abnormalities during On-treatment period are reported. On-Treatment was defined as values collected after the date of the first dose of test article until the last date of test article +28 days.

Bosutinib

Imatinib

Number of Participants With Laboratory Test Abnormalities Based on National Cancer Institute Common Terminology Criteria for AEs (NCI CTCAE) Version 4.03

Laboratory parameters included hematological (haemoglobin, lymphocytes [absolute], neutrophils [absolute], platelets and leukocytes) and biochemistry (albumin, alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, amylase, bilirubin, creatinine kinase, calcium, creatinine, glucose, potassium, lipase, magnesium, phosphate, sodium, urate) parameters. Abnormalities in laboratory tests were graded by NCI CTCAE version 4.03 as Grade 1= mild; Grade 2= moderate; Grade 3= severe and Grade 4= life-threatening or disabling. The number of participants with laboratory test abnormalities were reported.

Bosutinib

Grade 1

Grade 2

Grade 3

Grade 4

Imatinib

Grade 1

Grade 2

Grade 3

Grade 4

Number of Participants With Clinically Significant Electrocardiogram (ECG) Abnormalities

Criteria for ECG abnormalities included heart rate: increase of >15 bpm from baseline value and >=120 bpm, decrease of >15 bpm from baseline value and <=45 bpm; PR interval: change of >=20 msec from baseline value and >=220 milliseconds (msec); QRS interval >=120 msec; QTcB interval >500 msec, increase of >60 msec from baseline; >450 msec (Men) or >470 msec (Women). QT interval using Fridericia's correction (QTcF) >500 msec, increase of >60 msec from baseline, >450 msec (Men) or >470 msec (Women). The number of participants with ECG abnormalities during On-treatment period are reported. On-Treatment was defined as values collected after the date of the first dose of test article up until the last date of test article +28 days.

Bosutinib

Imatinib

Number of Participants With Adverse Events (AEs) Leading to Study Drug Discontinuation

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship.

Bosutinib

Imatinib

Number of Participants With Treatment-Emergent Adverse Events by National Cancer Institute Common Terminology Criteria for AEs (NCI CTCAE) (Version 4.0)

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. AE was assessed according to severity grading based on NCI CTCAE version 4.0. Grade 1 =mild; Grade 2 =moderate; Grade 3 =severe or medically significant but not immediately life-threatening, hospitalization or prolongation of hospitalization indicated; Grade 4 =life-threatening or disabling, urgent intervention indicated; Grade 5 =death. Treatment-emergent events were events between first dose of study drug and up to 60 months that were absent before treatment that worsened relative to pretreatment state. If the same participant in a given treatment had more than 1 adverse event, only the maximum CTCAE was reported.

Bosutinib

Grade 1

Grade 2

Grade 3

Grade 4

Grade 5

Imatinib

Grade 1

Grade 2

Grade 3

Grade 4

Grade 5

Total

536
Participants

Age, Continuous

50.9
years (Mean)
Standard Deviation: 14.91

Sex: Female, Male

Overall Study

Bosutinib

Imatinib

Drop/Withdrawal Reasons

Bosutinib

Imatinib